<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
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  <title>Document</title>
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<body>
 
  
<script>
  function  handleData(arr,flag=true) {
        
     let sum = 0 
     for(let i = 0; i<arr.length; i++){
       sum += arr[i]

     }
     let average = sum/arr.length
         if(flag) return sum
         else return average
        
  }
  let arr = [1,0,23,567,456]
  let res=handleData(arr,true)
  console.log(res);
</script>
</body>
</html>